Working with Backerboard

For most tile installations, you’ll want to use ¼″-thick
backerboard (Hardibacker). This fiber-cement sheet material is denser, cuts
cleaner, and lays flatter than cementboard.

One thing to be aware of is that you don’t want to use standard tools
to machine backerboard, as it dulls blades incredibly fast. For a few
dollars, you can pick up all the tools you’ll need at your local
hardware store.

To make a long, straight cut, the main tool that’s required is a
scoring blade. This is a hooked utility knife blade that fits in a
fixed-blade utility knife. It’s less likely to snap or dull than a
standard blade. Use it to score the cutline, and then snap the backerboard
as shown at left.

For smaller notches, a carbide-grit hacksaw blade comes in handy (I use a
Stanley 15-410). Pliers and a file also help with this task (Figs.
1-3). And for mounting backerboard, special backerboard screws are
available that countersink flush with the surface.

For a small notch, score both lines. Cut one line with a carbide-grit
hacksaw blade.

Pliers provide leverage as you snap the waste piece free to form the
notch.

A rasp makes quick work of smoothing the broken edge of the
backerboard.